Oil found in the bellows Mercruiser 3.0 + PreAlpha OD

alesk565

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Sep 13, 2015
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Hi captains,

I would like to get your opinion on this. Setup: Mercruiser 3.0 (from late 60?s) + PreAlpha outdrive.

Removed my outdrive today and i found oil in the driveshaft bellow as seen in the picture attached. No oil in the exhaust bellow...
I noticed that one of the two orings on the driveshaft fast broken (could have happend upon the removal aswell I guess).

Could this oil possibly come from anywhere but the outdrive?
I'm just asking since I did renovate the upper part of the outdrive last winter and I did a pressure check prior to installing.

Further info.
I drained the engine (from oil) last week and that oil was black.
I drained the lower part of the outdrive last week and that oil was black as well (two different oil systems on those old outdrives)
Also changed the bellows, shift cable and impeller last winter.
When I bought the boat there was oil in the bellows aswell, and since the outdrives upper part was rusty inside. I gave it some fresh bearings and gaskets.


Best regards,
Alexander
 

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Bt Doctur

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oil in the bellows can only come from the upper unit input shaft seal or input yoke
 

Rick Stephens

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When you smell that oil, does it smell like gear oil or not much smell at all? A little bit of water in the bellows will wash all the grease off your gimbal bearing and u-joints and create a convincing slurry of water and grease. Gear lube has a distinctive smell to it which the grease does not have.
 

alesk565

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It does smell more of "old rear car axle oil".
Since the OD oil only is 6 month (and 15hrs) old I find it strange that it would smell this much already.

Based on your information, the distinctive smell, it's probably OD oil? I will perform pressure check asap.

Thank for the respond.
 

Watermann

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You should be noticing that the OD oil level is low if it's leaking into the bellows.
 

Rick Stephens

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Gear lube smells out of the bottle new. Grease is usually smell free. Agree, it's time to pressure test.

I just redid the seals in my upper for the first time this last weekend. Mines a Gen2, so different procedure. But still not bad following the manual. If I'm not mistaken it is pretty straight forward on the pre-Alpha with the input shaft bearings behind the yoke being torqued to a given number. The Gen 2 requires a rolling torque set, which also requires a spendy little torque indicator tool. I think you get to avoid that with your pre Alpha.
 

alesk565

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Sep 13, 2015
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Waterman:
True, the problem is that the upper unit cannot be checked easily on my drive (maybe I can sort that out). But I tried in an easy manner and tought that it was still full, which was obviously not correct.

Rick:
Great to hear and I hope it went well;) you probably did better than me, since I managed to screw it up som how. As you say it's easier on mine since I can torque to a specific amount. (Before I understood that I was looking for different options to check the 4 Nm without having to buy that tool, like using a luggage scale and a lace spinned around the axle....guess I'm a bit cheap..)

Anyway, thanks for the advices and the help and I will get back with the error when found (or new questions?). In order to provide the wonderful forum with information.
 

alesk565

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No Title

Hello again,

I'm not sure whether I should continue on this thread or start a new one..but finally I have started the error check:

I made a pressure test and it seems like the pressure was okay. So it seems to be sealed correctly. But, I disassembled the upper part (lifting the lid and removed the yoke) and there was no oil left in the upper housing. Can the case be that the oil sneaks out when the drive is running? Like a concentric runout that only appears at high rpms? Or can it be that the seal doesn't seal over an area large enough since the shaft is rusty (attached picture)?

Thank you for answers and ideas.
 

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Watermann

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The oil only settles back to the level of the vent plug so you won't see the upper filled with oil when you pull off the top cap.
 

Grub54891

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If you are checking the pressure with oil in the drive, you will never find the leak. They must be drained before preforming the test. Air moves easier than oil.
 

Bondo

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Ayuh,.... As rusted as that shaft is, No Way that seal holds air,.....

A Speedi-sleeve might fix it,....
 

alesk565

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If you are checking the pressure with oil in the drive, you will never find the leak. They must be drained before preforming the test. Air moves easier than oil.

The oil level was below the shaft so it was air inside the drive when testing it.

Bondo: I will look that up:)
 

Bondo

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Bondo: I will look that up
smile.gif

Ayuh,.... SKF 99225 should be the one,....
 
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